A northern white rhinoceros near the equator during translocation to Ol Pejeta Conservancy.

One of the northern white rhinos translocated to Ol Pejeta is now living in a semiwild state.

The zoo population is declining, and northern whites have rarely reproduced in captivity. There are now only three northern white rhinos left:

Sudan, a 45-year-old male (as of 2018[update]), was caught from the wild in Sudan in 1975 at about 3 years of age. He is the father of Najin and the late Nabire.[3][4] In March 2018, his state seriously deteriorated despite intensive care due to a recurrent infection in his right hind leg.[5]

Najin, a female, was born in captivity in 1989. She was the mother of the departed Fatu.[6] Her mother was Nasima and her father is Sudan.[3]

Fatu, a female, was born in captivity in 2000.[6] Her mother is Najin and her father was Saut.[7]

They all belong to the Dvůr Králové Zoo in the Czech Republic, but live in Ol Pejeta Conservancy in Kenya, Africa.[8] They arrived at the conservancy after an air and road trip on 20 December 2009,[9] along with another northern white rhino from the Dvůr Králové Zoo, Suni. However, Suni, a male born at Dvůr Králové Zoo in 1980, died from natural causes in Ol Pejeta Conservancy in 2014.[10][11]

The rhinos, under constant watch by specialists and staff, lived in specially constructed bomas with access to a 400×400-metre paddock area, allowing them to acclimatize to their new surroundings.[citation needed] To prevent any unnecessary injuries they might inflict on each other while interacting in their fenced area, and give their horns an opportunity to regrow to a natural shape (as their front horns had grown bent by much rubbing against enclosure bars in captivity), all the rhinos were sedated and their horns were sawn off. This also made them less vulnerable to the poaching that drove their species to near extinction, as the horn is what the poachers are after. In place of their horns, radio transmitters have been installed to allow closer monitoring of their whereabouts.[12] They are protected round-the-clock by armed guards.[13] Poachers have been selling their horns for $50,000 per kilo.[14]

Since May 2010, the northern white rhino male Sudan was moved from the initial holding pens to a much larger 700-acre (2.8 km2) semiwild enclosure. There he roams among many African animals, including several southern white rhino females and many plains animals. On 26 October 2011, the females were coaxed into the larger enclosure. Because Najin was overly protective of her daughter Fatu's chance at mating, one of the two moved back into the smaller enclosure two weeks later.[citation needed]

Until 2011, the progress of this attempt at saving the northern white rhinoceros was documented on the initiative's website;[15] and their life in Ol Pejeta Conservancy is commented on on the Conservancy's website. Several documentaries are in the works, including an episode of Ol Pejeta Diaries entitled "Return of the African Titans" for Oasis HD Canada fall 2010, and a follow-up half-hour episode to follow. This translocation is also the subject of a BBC Last Chance to See special entitled "Return of the Rhino,"[16] presented by Stephen Fry and the zoologist Mark Carwardine; the TV program reported at the end that the two pairs of rhinos were "flirting."

On 25 April 2012 and on 27 May 2012 Suni and Najin mated.[17] Pregnancy of the female rhinos was monitored weekly.[18] Rhinoceros gestation period takes 16 to 18 months,[19] so in January 2014 the Conservancy considered Najin not pregnant, and a male southern white rhino from Lewa Wildlife Conservancy was put to Najin and Fatu enclosure in Ol Pejeta to at least intercross the subspecies. To achieve this, both female northern white rhinos were separated from their male counterparts, which prevents them, for the time being, from producing a pure northern white rhino offspring.[20][21] In 2015, however, test conducted by Czech specialists revealed that neither of the females are "capable of natural reproduction".[22][23]

At the end of 2015, scientists from the Leibniz Institute for Zoo and Wildlife Research, San Diego Zoo Global, Tiergarten Schönbrunn and Dvůr Králové Zoo developed a plan to reproduce northern white rhinos using natural gametes of the living rhinos and induced pluripotent stem cells. Subsequently, in the future, it might be possible to specifically mature the cells into specific cells such as neurons and muscle cells, in a similar way in which Katsuhiko Hayashi has grown mice out of simple skin cells. The DNA of a dozen northern white rhinos has been preserved in genetic banks in Berlin and San Diego.[24]

In 2017, Ol Pejeta Conservancy teamed up with Tinder to launch a fund raising campaign in order to recover this species. Therefore, they created a Tinder account for Sudan, the last standing male of northern white rhinos, and the app's users could swipe right to make their donations for the development of breeding methods.[25] On 1st Jan 2018 the campaign fund had reached £42'153 (target £9m).[26]

Poachers reduced their population from 500 to 15 in the 1970s and 1980s. From the early 1990s through mid-2003, the population recovered to more than 32 animals.[28][29] Since mid-2003, poaching has intensified and further reduced the wild population.[28]

The last known surviving population of wild northern white rhinos was in Garamba National Park, Democratic Republic of the Congo (DRC).

In January 2005, the government of the DRC approved a two-part plan for five northern white rhinos to be moved from Garamba National Park to a wildlife sanctuary in Kenya. The second part commits the government and its international partners to increase conservation efforts in Garamba, so the northern white rhinos can be returned when it is safe again.[30] However, the translocation did not occur.

In August 2005, ground and aerial surveys conducted under the direction of African Parks Foundation and the African Rhino Specialist Group (ARSG) had only found four animals, a solitary adult male and a group of one adult male and two adult females.[31] They were the last known wild northern white rhinos, according to the World Wide Fund for Nature.[32]

In June 2008, it was reported that the species may have gone extinct in the wild, since there has been no sighting of these four known remaining individuals since 2006, or of their signs since 2007, despite intensive systematic ground and aerial searches in 2008.[2][33] One carcass has been found.[2][34][35] On 28 November 2009, two Russian helicopter pilots reported seeing Northern White Rhinos in southern Sudan.[36] It was assumed that the three rhinoceroses that were spotted belong to this subspecies, as other rhinoceroses have not been living in the area for a long time.[37] However, as of August 2011, no other sightings have been reported,[2] and this population is now considered to have probably gone extinct.[2]

At the beginning of 2015, the fully captive northern white rhino population consisted of only two animals maintained in two zoological institutions: in the United States (San Diego Zoo Safari Park) and the Czech Republic (Dvůr Králové Zoo). However, both of them died later the same year, and no zoo in the world has any northern white rhinos any longer.

In 1975, the Dvůr Králové Zoo, located in Dvůr Králové nad Labem, Czech Republic, got six northern white rhinos from Sudan and, in later years, two more from English zoos. One rhino from an English zoo arrived pregnant. The zoo is the only one in the world where northern white rhinos birthed offspring; the current world population consists of one of those rhinos and their shared descendants.[38][3][7]

Former residents include:

Ben, a male wild born in Africa in about 1951. He was transferred to Dvůr Králové Zoo from a faculty in England and died 25 June 1990.[3]

Nasima, a female wild born in Uganda in about 1965. She was transferred pregnant to Dvůr Králové Zoo from a faculty in England. She was the mother of Nasi, Suni, Nabire, and Najin. She birthed four out of five Northern White Rhino calves born in captivity, making her the most fruitful Northern White in captivity to date.[3][4] She died in 1992 at about age 27.[7]

Saut, a male caught from the wild in Sudan in 1975 at about 3 years of age.[3] He was the father of Suni and Fatu. He was loaned to San Diego Zoo Safari Park by Dvůr Králové Zoo from 1989 until 1998 when he was returned to Dvůr Králové Zoo. He mated with females at both faculties.[7][39] He died in August 2006 around age 33.[40]

Nuri, a female caught from the wild in Sudan in 1975 at about 3 years of age. She died 4 January 1982 at about age 10.[3]

Nesari, a female caught from the wild in Sudan in 1975 at about 3 years of age. She died in 2011 at age 39.[41][3]

Nasi, a female born at Dvůr Králové Zoo on 11 November 1977 and died in 2007. Her mother was Nasima and her father was a southern white rhino, which made her a northern and southern white rhino hybrid.[3][42]

Suni, a male born at Dvůr Králové Zoo on 8 June 1980. He was the half-brother of Najin and Fatu, but through different parents. His mother was Nasima and his father was Saut.[7][3] He had mated while in zoos. Was transferred to Ol Pejeta Conservancy in 2009. Some of his sperm has been collected and frozen. On 17 October 2014, he died from natural causes, probably old age.[10][11]

Nabire, born at Dvůr Králové Zoo on 15 November 1983. Her mother was Nasima and her father was Sudan. She died on 27 July 2015.[3][43]

Dvůr Králové Zoo sent Suni and three other northern white rhinoceros which are still alive, one male and two females, to the Ol Pejeta Conservancy in Kenya on 19 December 2009[44] in a joint effort by the zoo, Fauna and Flora International, Back to Africa, Lewa, and Kenya Wildlife Service. Hoping to stimulate the rhinos' sexual appetite, the zoo decided to send them back into their natural habitat in Kenya. The agreement with the Kenyan government expects the rhinos never to be returned to the Czech Republic.

Dvůr Králové was the only zoo in which northern white rhinos produced offspring; the last calf was born in 2000.[45]

The female named Nabire stayed in Dvůr Králové Zoo, because, as Jan Stejskal, a projects coordinator at the zoo, stated, "she is no longer capable of breeding naturally. But it seems she has one healthy ovary and this could provide us with material from which to create an embryo in artificial conditions."[45] Efforts to do so began in autumn 2014.[46] Immediately after the death of Nabire in 2015, her ovary with four oocytes was removed and transferred to a laboratory in Cremona, Italy. The laboratory was able to extract two egg cells and fertilise them. However, without consulting the Dvůr Králové Zoo, the semen of a southern white rhino was used instead of a northern white rhino, which the zoo considers a wasted opportunity.[47]

Dinka, a male caught from the wild in Sudan in 1957 at about 5 years of age, who arrived from another U.S. zoo in 1972. He died in 1974.[7]

Bill, a male caught from the wild in Sudan in 1956 at about 4 years of age, who arrived from another U.S. zoo in 1972. He died in 1975.[7]

Lucy, a male caught from the wild in Sudan in 1956 at about 4 years of age, who arrived from another U.S. zoo in 1972. He died in 1979.[7]

Joyce, a female caught from the wild in Sudan in 1957 at about 5 years of age, who arrived from another U.S. zoo in 1972. She died in 1996.[7]

Saut, a male caught from the wild in Sudan in 1975 at about 3 years of age, who was on loan from Dvůr Králové Zoo from 1989-1998. He died in August 2006 at about age 33.[7][40]

Nadi, a female caught from the wild in Sudan in 1975 at about 3 years of age, who was on loan since 1989 from Dvůr Králové Zoo. She died on 30 May 2007 at about age 35.[48][7]

Angalifu, a male caught from the wild in Sudan in 1973 at about 1 year of age, who was on loan since 1990 from Khartoum Zoo in Khartoum. He died on 14 December 2014 at about age 42.[1][7]

Nola, a female caught from the wild in Sudan in 1975 at about 1 year of age, who was on loan since 1989 from Dvůr Králové Zoo.[49][50][51] She died on 22 November 2015 at about age 41.[52]

The San Diego Wild Animal Park provided Angalifu's semen to female rhinos at the Dvůr Králové Zoo but the insemination attempts were unsuccessful. The only reproductive animals of this subspecies were transported to Ol Pejeta Conservancy in Kenya.

In 2016, it was reported that scientists were exploring alternatives (such as artificial insemination, in vitro fertilization and embryo transfer) to develop northern white rhino embryos and implant them in female southern white rhinos at the San Diego Zoo.[53]

Following the phylogenetic species concept, recent research has suggested the northern white rhinoceros may be an altogether different species, rather than a subspecies of white rhinoceros, in which case the correct scientific name for the former is Ceratotherium cottoni. Distinct morphological and genetic differences suggest the two proposed species have been separated for at least a million years.[58] However, the results of the research were not universally accepted by other scientists.[2]